Atypical cells found in mole

Hi I recently had a small, mostly flat, black mole removed from my leg. When I called yesterday for my results, my dermatologist's PA told me that they found atypical cells and they sent it off to UC San Fransisco for a second look, which they only usually do for about four percent of their specimen. She told me not to stress, and that there is no black and white answer for these things, but I can't help but be stressed. She said the doctor would have to remove more of the skin around where the mole was, but they need to know how much. Should I be worried? Or is it possible that this may be absolutely no big deal? I've spent a lot of time in tanning beds, and I only stopped going to them a year ago, when I realized how stupid I am for doing something so dangerous. I'm fair complected naturally with light eyes...and I have A LOT of moles and freckles. Am I in big trouble?
Thank you

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